<template>
  <!-- 轮播图组件 -->
  <div class="xtx-carousel" @mouseenter="stop()" @mouseleave="star()">
    <ul class="carousel-body">
      <li class="carousel-item" v-for="(item, i) in sliders" :key="i" :class="{fade: index === i}">
        <!-- 主图区域 -->
        <router-link :to="`/product/${item.id}`" v-if="item.imgUrl">
          <img :src="item.imgUrl" alt="">
        </router-link>
        <div class="slider" v-else>
          <router-link :to="`/product/${goods.id}`" v-for="goods in item" :key="goods.id">
            <img :src="goods.picture" alt="">
            <p class="name ellipsis">{{ goods.name }}</p>
            <p class="price">{{ goods.price }}</p>
          </router-link>
        </div>
      </li>
    </ul>
    <!-- 上、下一张按钮 -->
    <a href="javascript:;" class="carousel-btn prev" @click="toggle(-1)"><i class="iconfont icon-angle-left"></i></a>
    <a href="javascript:;" class="carousel-btn next" @click="toggle(1)"><i class="iconfont icon-angle-right"></i></a>

    <!-- 下方小图标 -->
    <div class="carousel-indicator">
      <span @click="index = i" class="" v-for="item,i in sliders" :key="i" :class="{active: index === i}"></span>
    </div>
  </div>
</template>

<script>
import { onUnmounted, ref, watch } from 'vue'
export default {
  name: 'XtxCarousel',
  props: {
    sliders: {
      type: Array,
      default: () => []
    },
    // 轮播图自动播放停留的事件
    duration: {
      type: Number,
      default: 3000
    },
    // 是否开启自动轮播功能
    autoPlay: {
      type: Boolean,
      default: false
    }
  },
  setup (props) {
    // 默认显示的广告图片
    const index = ref(0)
    // 设置自动轮播功能
    let times = null

    const autoPlayFn = () => {
      clearInterval(times)
      times = setInterval(() => {
        index.value++

        // 判断当前的广告图片是否是最后一张，是的话将index重置为0
        if (index.value >= props.sliders.length) {
          index.value = 0
        }
      }, props.duration)
    }

    // 开启侦听器 第一个参数为需要监听的数据 第二个参数为数据发生改变后需要触发的函数或事件
    watch(() => props.sliders, (newValue) => {
      // 如果有数据的话 开启自动播放
      if (newValue.length && props.autoPlay) {
        index.value = 0
        autoPlayFn()
      }
    }, { immediate: true })

    // 当鼠标移除时开启定时器，鼠标进入时停止定时器
    // 停止定时器
    const stop = () => {
      if (times) clearInterval(times)
    }

    // 开启定时器
    const star = () => {
      if (props.sliders.length && props.autoPlay) {
        autoPlayFn()
      }
    }

    // 上一张下一张
    const toggle = (step) => {
      const newStep = index.value + step

      // 点击下一张当超出的时候，index则重置为0
      if (newStep >= props.sliders.length) {
        index.value = 0
        return
      }

      // 点击上一张时超出范围则回到最后一张广告图
      if (newStep < 0) {
        index.value = props.sliders.length - 1
        return
      }

      // 其他正常经行
      index.value = newStep
    }

    // 组件小号 清理定时器
    onUnmounted(() => {
      clearInterval(times)
    })
    return { index, stop, star, toggle }
  }
}
</script>

<style lang="less" scoped>
.xtx-carousel {
  width: 100%;
  height: 100%;
  min-width: 300px;
  min-height: 150px;
  position: relative;
  .carousel {
    &-body {
      width: 100%;
      height: 100%;
    }
    &-item {
      width: 100%;
      height: 100%;
      position: absolute;
      left: 0;
      top: 0;
      opacity: 0;
      transition: opacity 0.5s linear; // 动画显示轮播图
      &.fade { // 当广告图片当前的索引值等于 index.value时 添加此样式类名
        opacity: 1;
        z-index: 1;
      }
      img {
        width: 100%;
        height: 100%;
      }
    }
    &-indicator {
      position: absolute;
      left: 0;
      bottom: 20px;
      z-index: 2;
      width: 100%;
      text-align: center;
      span {
        display: inline-block;
        width: 12px;
        height: 12px;
        background: rgba(0, 0, 0, 0.2);
        border-radius: 50%;
        cursor: pointer;
        ~ span {
          margin-left: 12px;
        }
        &.active {
          background: #fff;
        }
      }
    }
    &-btn {
      width: 44px;
      height: 44px;
      background: rgba(0, 0, 0, 0.2);
      color: #fff;
      border-radius: 50%;
      position: absolute;
      top: 228px;
      z-index: 2;
      text-align: center;
      line-height: 44px;
      opacity: 0;
      transition: all 0.5s;
      &.prev {
        left: 20px;
      }
      &.next {
        right: 20px;
      }
    }
  }
  &:hover {
    .carousel-btn {
      opacity: 1;
    }
  }

  .slider {
    display: flex;
    justify-content: center;
    padding: 0 40px;
    >a {
      width: 240px;
      text-align: center;
      img {
        padding: 20px;
        width: 230px !important;
        height: 230px !important;
      }
      .name {
        font-size: 16px;
        color: #666;
        padding: 0 40px;
      }
      .price {
        font-size: 16px;
        color: @priceColor;
        margin-top: 15px;
      }
    }
  }
}
</style>
